Bit for lifting tongs



Aug. 17, 1943. v F; MEJER 2,326,962

BIT FOR LIFTING TONGS Filed June 22, 1942 IEVENTOR FRED MEIER,

9% ifs L flarney.

Patented Aug. 17, 1943 UNITED STATES PATENT OFFICE BIT FOR LIFTING TONGS Fred lvleier, Chicago, Ill. Application June 22, 1942, sci-151ml. 447,992 3 Claims. (01". 294 11s) This invention'relates to bits for lifting tongs such as those employed in the handling of heavy objects, and more particularly to those which are used for handling metallic ingots, although not limited thereto,

In the manufacture of steel products, the ingots which are formed of the molten steel are slabs, or billets, it is necessary to equalize its temperature throughout to roughly from about 2200 F. to 2400 F. This temperature equalization i accomplished by reheating in a soaking pit or heating chamber into which it is lowered and withdrawn by means of toggle-actuated tongs carried by and operated through an overhead traveling crane.

It will be readily understood that such an object (viz., a heavy-highlyheatedsmetallicdngotl presents unusal handling problems. The working faces of the toggle-actuated tongs are usually provided with an opposed pair of conical bits the most adjacent ends of which are pointed; and through the toggle action of the tongs are forced into the relatively soft, highly-heated metal of the ingot. While the indentations thus made permit of the relatively safe handling of the ingot, they break the skin thereof and leave marks which are difficult to remove. Frequently these marks extend to a depth of inch to inch, and they can be removed only by conditioning, which may be accomplished either by chipping or scarfing, manual or otherwise. However accomplished, conditioning involves considerable expense.

In addition to the foregoing difficulties, conically-shaped bits are characterized by lack of longevity, as they must be redressed after several hours use. Such redressing,while of itself comparatively easy and inexpensive, is undesirable for the reason that the lifting tongs are out of service during the removal of the worn bits and the substitution thereof of those which have been suitably dressed.

Another disadvantage of the conically-shaped bits of the prior art is that their working ends when in use acquire considerable heat and frequently must be cooled, such as by dipping in water. Such cooling is objectionable for the reason that, as in the case of replacement, it curtails the productive work of the lifting tongs, or other machine employed to operate the bits.

It is among the objects of the present invention to provide bits for lifting tongs which eliminate damage to the object being lifted but which at the same time operate with considerable safety in that they obtain a very firm grip.

Another object is the provision of bits of the class described which do not require attention for any reason, whereby there is increased the number of ways in which the principles of the invention may be employed.

In said drawing:

Figure 1 is a fragmentary elevation, partly in section, of lifting tongs of the type commonly employed for lifting metallic ingots and other heavy objects, illustrating in association therewith the device of the present invention.

Figure 2 is an elevation, partly in section, illustrating the device of the present invention and its manner of association with one of the arms of the lifting tongs.

Figure 3 is an end view of the work-contacting surface of the device.

Figure 4 is a sectional view of a guiding instrumentality which forms part ofthe device and which functions to maintain the work-contacting surface of Figure 3 in the desired relationship with respect to the lifting tongs.

Fig. 5 is an elevation-showing a modification of the ball member;

Fig. 6 is a plan view of the modification shown in Fig. 5.

Referring more particularly to the' drawing, the numeral 2 generally designates a pair of lifting tongs such as those which are used in the lifting of metallic ingots and other heavy objects in steel mills and other industrial plants.

While not shown herein, the lower ends of the tongs 2 are usually provided on their adjacent faces with opposed comically-shaped bits having their adjacent ends pointed or slightly concave in order to penetrate into the body of the workobject.

According to the techings of the present invention, the lower ends of the tongs 2 are provided 'ments I2.

with aligned frusto-conical apertures 3, the inner ends of which are of smallest diameter. On the adjacent faces of the lower ends of the tongs 2, and centrally communicating with the smaller ends of the frusto-conical apertures 3, are substantially semi-spheroidal recesses or sockets 5. On their opposite faces the lower ends of the tongs 2 are provided with cylindrical recesses 6 the bottoms of which are convexedly substantially semi-spheroidal, as shown at 1, and which centrally communicate with the larger ends of the frusto-conical apertures 3.

Seated in each of the substantially semispheroidal recesses 5, and projecting slightly therefrom, is a substantially semi-spheroidal insert or ball 9 carrying on its bottom a projecting cylindrical stud I0. These cylindrical studs ID are adapted to extend through the frustoconical apertures 3 and terminate slightly beyond the substantially semi-spheroidal convex bottoms I of the cylindrical recesses 6; and each carries in extended relationship with respect thereto a concentric cylindrical stud ll of reduced diameter, the connecting surfaces of the said studs I and II providing relatively flat annular abut- Carried on the cylindrical stud H of reduced diameter is a retainer plate, generally designated at l5, the same comprising an annular member having a central cylindrical bore l6. One side of each of the retainer plates is provided with a substantially semi-spheroidal recess I1, the bottoms of the said recesses I'I being adapted for frictional engagement with the substantially semi-spheroidal convex bottoms I of the cylindrical recesses 6. Formed integral with and projecting from the opposite side of each of the retainer plates I is a cylindrical boss I9 through which the central cylindrical bore IB extends. Each of these central cylindrical bosses I9 of reduced diameter is provided with a centrally transverse aperture 2|. Thus the apertures 2| are adapted to receive pins 23 which extend through centrally transverse apertures 24 in the cylindrical studs II which are part of the substantially semi-spheroidal inserts or balls 9.

According to the foregoing construction and arrangement, it will be perceived that due to the cylindrical formation of the studs 19 which extend through the materially larger frusto-conical apertures 3 in the lifting tongs 2, there is provided a ball-and-socket relationship whereby the inserts or balls 9 are permitted universal movement of limited character.

The adjacent faces of the inserts or balls 9 are preferably corrugated or roughened by a plurality of shallow blunt projections or knobs 25 which increase the gripping action. It will be understood, however, that the work-contacting surfaces of the inserts or balls 9 may be flat or in a single plane when the side surfaces of the work-object (such as the ingot aforesaid) are smooth and level. On the other hand, the sides of the ingot are often corrugated, in which case it is preferable to provide the inserts or balls 9 with curved or partially cylindrical work-contacting surfaces 30 as shown in Figs. 5 and 6,

the radius of curvature approximately corresponding to the center corrugation of the workobject (or ingot).

Due to the concavo-conyex or ball-and-socket relationship of the bit and its holder, it can freely adjust itself to the angularity of the sides of the ingot or other work-object, and thus obtain a uniform and more evenly distributed contact area, whereby there is provided a more secure hold with a considerably reduced unit pressure. In this manner the skin will not be broken in the manner characteristic of the prior art lifting bits which were referred to hereinbefore.

The limited universal movement accorded the bits of the present invention permits the ingot or other work-object to swing in true equilibrium. Moreover, there is facilitated the turning of the ingot (or other work-object) upside down if for any reason such is desired, as in the case of the delivery of aningot to the rolling mill approach table, the same being often required in rolling practice.

While I have shown and described certain specific embodiments of the present invention, it will be seen that I do not wish to be limited exactly thereto, since various modifications may be made without departing from the scope of the invention as defined in the appended claims.

I claim:

1. A lifting bit for lifting apparatus including at least one lifting element, said lifting bit and said lifting element providing contact surfaces in freely movable ball-and-socket relationship, a stud carried by the bottom of said lifting bit and extending through said lifting element, and means for retaining said stud against axial displacement, the work-contacting surface of said lifting bit projecting from the adjacent surface of said lifting element.

2. A lifting bit for'lifting apparatus including at least one lifting element, said lifting bit comprising a ball member adapted to contact said lifting element, a stud carried by the bottom of said ball member and extending through said lifting element, and means for retaining said stud against axial displacement, the Workcontacting surface of said lifting bit projecting from the adjacent surface of said lifting element.

3. A lifting bit for lifting apparatus including at least one lifting element, said lifting bit comprising a ball member adapted to contact a socket in said lifting element, a stud carried by the bottom of said ball member and extending through an opening in said lifting element, the diameter of said opening .being substantially greater than that of said stud, and a retainer plate fastened to said stud, said retainer plate having a semi-spheroidal recess in the side adjacent said opening for engagement with a corresponding semi-spheroidal surface on said lifting member, the Work-contacting surface of said lifting bit projecting from the adjacent surface of said lifting element.

FRED MEIER. 

